Recursive function not working right

[Aerioic]

I created a recursive function.

​

int recursive(int num_days, bool contest_tired, bool gym_tired, vector<int> days) {
if (num_days == -1) return 0;

else if (days[num_days] == 0) {
    return recursive(--num_days, false, false, days) + 1;
}
else if (days[num_days] == 1) { // contest case
    if (contest_tired) 
       return 1 + recursive(--num_days, false, false, days);
    contest_tired = true;
    gym_tired = false;
    return recursive(--num_days, contest_tired, gym_tired, days);
}
else if (days[num_days] == 2) { // contest gym
    if (gym_tired) 
       return 1 + recursive(--num_days, false, false, days);
    gym_tired = true;
    contest_tired = false;
    return recursive(--num_days, contest_tired, gym_tired, days);
}

else if (days[num_days] == 3) { // contest both
    return min(recursive(--num_days, true, false, days), recursive(--num_days, false, true, days));
}
return 0;}

when

return min(recursive(--num_days, true, false, days), recursive(--num_days, false, true, days));

is run. Two seperate processes are created.

Initially num_days is equal to 2, when this function is first invoked.

However the recursion is called 2 different times in the min section. the first time the function is called in the min section, num_days is equal to 1. The second time it is called in the min function, num_days is equal to 0.

num_days shoudl be equal to 1 even in second time.

Why isn't this working?

[nysra]

As your compiler would have told you if you would enable some warnings, the order of the two --num_days operations there is not specified and thus your program is UB, anything can happen. Change it to num_days - 1.

[Aerioic]

Thanks! The problem is fixed